cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations termios/OFDEL.c -o termios/OFDEL -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
termios/OFDEL.c:8:17: error: use of undeclared identifier 'OFDEL'
int const foo = OFDEL;
                ^
1 error generated.